The importance of etching aluminum and aluminum alloys has increased significantly within the last several years. As the electronics industry has moved into production of very large scale integrated circuits (VLSI), the need to find a method of etching aluminum which meets the requirements for VLSI production has likewise grown in importance.
One of the critical problems which must be solved in order to etch aluminum efficiently is the variance in onset of etching, i.e. the induction period, when aluminum or its alloys are etched in chlorinated gases. The variable induction period in aluminum etching leads to non-reproducible etch times from run-to-run, a decided disadvantage in a production situation. Further, variance in induction period expands process time and reduces throughput, likewise disadvantageous. A simple yet effective solution to this problem is provided in accordance with this invention.